Spatial and Cellular Architecture of the Glioblastoma Microenvironment Associated with Tumor-Infiltrating Lymphocyte Expansion

Abstract

Tumor-infiltrating lymphocyte (TIL) therapy is effective in several tumor types; however, its feasibility in immune subversive tumors like glioblastoma is unclear. We expanded TILs from glioblastoma specimens and observed marked variability in yield, composition, function, and TCR clonality. By interrogating TILs expanded ex vivo alongside their sourced glioma tissue, we sought to identify determinants of successful (TIL+) vs unsuccessful TIL expansion (TIL-). Expanded TILs were predominantly effector memory CD4 cells and exhibited oligoclonal TCR enrichment. Despite similar T cell abundance in TIL vs TIL- tumors, TIL tumors exhibited distinct spatial organization and cellular interactions, including increased endothelial-immune interactions/ proximity and enrichment of vascular-associated niches. CD4 T cells localized near CD68 macrophages in TIL tumors, while they were positioned near CD163 CD206 macrophages in TIL- tumors. Thus, TIL expansion and functionality are linked to spatial organization and myeloid context; these features may enable biomarker-driven stratification for future TIL therapy in gliomas.